This invention relates to an electronic musical instrument capable of generating information for musical tones used for an automatic performance by digital processing.
It is an object of the invention to provide an electronic musical instrument capable of processing note information which is suitable for use in automatic performance such as an automatic arpeggio performance and an automatic bass chord performance in which one or a plurality of tones are sequentially and repeatedly produced in a certain order and at a certain time interval.
There is a prior art electronic musical instrument which can perform an automatic arpeggio in which data of depressed keys in a keyboard is stored in a shift register and the tones of the depressed keys are selected one by one by scanning this shift register for producing the selected tones. In this prior art instrument, however, an order of selecting tones is constant for the selection is made simply by scanning the shift register and, accordingly, this instrument is not suitable for performing a complicated arpeggio.
According to the present invention, selection of a certain tone from among one or more tones specified by key depression is made by utilizing data of a previously produced tone. For selecting the note information, a combination of selection circuits or priority selection circuits in which the selection operation can be varied in accordance with control information is employed. In these selection circuits or priority selection circuits, data of a previously produced tone is utilized as a basis of selection. Storage means are provided for storing note information of a produced tone and the stored note information is used as the data of the previously produced tone. More specifically, priority selection circuits capable of changing a priority position in accordance with control information representing the priority position, i.e. priority information and capable also of changing a priority direction are employed and information representing a note name of a previously produced tone is utilized as the priority information for selecting information of a tone or tones which are higher (or lower) than the previously produced tone from among one or more tones specified by key depression. Further, information of a single tone (the highest or lowest tone) among the selected tone information is selected by another priority selection circuit capable of changing the priority direction. The single tone thus selected is a tone on a higher side (or a lower side) of the previously produced tone and this tone constitutes a next tone to be produced. In the above described manner, tones are sequentially produced one by one to produce an automatic arpeggio effect. Since the priority selection circuit can control the priority position or direction, selection of note information can be made in any complicated order or mode by changing contents of the control information when selection of each tone is made. Accordingly, a complicated automatic arpeggio can be performed. Further, the invention is applicable not only to the automatic arpeggio performance but to other automatic performances including an automatic bass performance in which tones to be produced are selected one by one.
It is another object of the invention to provide an electronic musical instrument which produces information of one or more tones which are in a predetermined note interval relation to a root tone selected by key depression and selects information of desired tones therefrom at a desired timing to produce tones corresponding to the selected information. In this instrument, a shift register having memory positions corresponding to notes of a chromatic scale (i.e., C-B) is provided, data representing note intervals of a desired chord is stored in this shift register and note information is provided to the respective data by shifting the data stored in the shift register in accordance with a root tone selected by key depression. The tone information thus provided with note information is selected one by one to perform a broken chord type automatic performance (Alberti bass) such as an automatic arpeggio and an automatic bass performance. Accordingly, tones of any complicated note interval relation can be produced in the automatic arpeggio performance.
It is another object of the invention to provide an electronic musical instrument in which processing means for suitably processing note information or the like obtained by depressing keys in the keyboard is commonly used, in time division multiplexing manner, for different automatic performance functions such as an automatic bass chord performance and an automatic arpeggio performance, thereby to eliminate the necessity of providing the processing means for each of the automatic performance function, that is, to permit a plurality of automatic performance functions to be effected with only one processing means.
The nature, utility and principle of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which like parts are designated by like reference numerals or characters.